Loading...
1/*
2 * Copyright (C) 2007 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19#include <linux/fs.h>
20#include <linux/pagemap.h>
21#include <linux/highmem.h>
22#include <linux/time.h>
23#include <linux/init.h>
24#include <linux/string.h>
25#include <linux/backing-dev.h>
26#include <linux/mpage.h>
27#include <linux/falloc.h>
28#include <linux/swap.h>
29#include <linux/writeback.h>
30#include <linux/statfs.h>
31#include <linux/compat.h>
32#include <linux/slab.h>
33#include "ctree.h"
34#include "disk-io.h"
35#include "transaction.h"
36#include "btrfs_inode.h"
37#include "ioctl.h"
38#include "print-tree.h"
39#include "tree-log.h"
40#include "locking.h"
41#include "compat.h"
42
43/*
44 * when auto defrag is enabled we
45 * queue up these defrag structs to remember which
46 * inodes need defragging passes
47 */
48struct inode_defrag {
49 struct rb_node rb_node;
50 /* objectid */
51 u64 ino;
52 /*
53 * transid where the defrag was added, we search for
54 * extents newer than this
55 */
56 u64 transid;
57
58 /* root objectid */
59 u64 root;
60
61 /* last offset we were able to defrag */
62 u64 last_offset;
63
64 /* if we've wrapped around back to zero once already */
65 int cycled;
66};
67
68static int __compare_inode_defrag(struct inode_defrag *defrag1,
69 struct inode_defrag *defrag2)
70{
71 if (defrag1->root > defrag2->root)
72 return 1;
73 else if (defrag1->root < defrag2->root)
74 return -1;
75 else if (defrag1->ino > defrag2->ino)
76 return 1;
77 else if (defrag1->ino < defrag2->ino)
78 return -1;
79 else
80 return 0;
81}
82
83/* pop a record for an inode into the defrag tree. The lock
84 * must be held already
85 *
86 * If you're inserting a record for an older transid than an
87 * existing record, the transid already in the tree is lowered
88 *
89 * If an existing record is found the defrag item you
90 * pass in is freed
91 */
92static void __btrfs_add_inode_defrag(struct inode *inode,
93 struct inode_defrag *defrag)
94{
95 struct btrfs_root *root = BTRFS_I(inode)->root;
96 struct inode_defrag *entry;
97 struct rb_node **p;
98 struct rb_node *parent = NULL;
99 int ret;
100
101 p = &root->fs_info->defrag_inodes.rb_node;
102 while (*p) {
103 parent = *p;
104 entry = rb_entry(parent, struct inode_defrag, rb_node);
105
106 ret = __compare_inode_defrag(defrag, entry);
107 if (ret < 0)
108 p = &parent->rb_left;
109 else if (ret > 0)
110 p = &parent->rb_right;
111 else {
112 /* if we're reinserting an entry for
113 * an old defrag run, make sure to
114 * lower the transid of our existing record
115 */
116 if (defrag->transid < entry->transid)
117 entry->transid = defrag->transid;
118 if (defrag->last_offset > entry->last_offset)
119 entry->last_offset = defrag->last_offset;
120 goto exists;
121 }
122 }
123 set_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags);
124 rb_link_node(&defrag->rb_node, parent, p);
125 rb_insert_color(&defrag->rb_node, &root->fs_info->defrag_inodes);
126 return;
127
128exists:
129 kfree(defrag);
130 return;
131
132}
133
134/*
135 * insert a defrag record for this inode if auto defrag is
136 * enabled
137 */
138int btrfs_add_inode_defrag(struct btrfs_trans_handle *trans,
139 struct inode *inode)
140{
141 struct btrfs_root *root = BTRFS_I(inode)->root;
142 struct inode_defrag *defrag;
143 u64 transid;
144
145 if (!btrfs_test_opt(root, AUTO_DEFRAG))
146 return 0;
147
148 if (btrfs_fs_closing(root->fs_info))
149 return 0;
150
151 if (test_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags))
152 return 0;
153
154 if (trans)
155 transid = trans->transid;
156 else
157 transid = BTRFS_I(inode)->root->last_trans;
158
159 defrag = kzalloc(sizeof(*defrag), GFP_NOFS);
160 if (!defrag)
161 return -ENOMEM;
162
163 defrag->ino = btrfs_ino(inode);
164 defrag->transid = transid;
165 defrag->root = root->root_key.objectid;
166
167 spin_lock(&root->fs_info->defrag_inodes_lock);
168 if (!test_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags))
169 __btrfs_add_inode_defrag(inode, defrag);
170 else
171 kfree(defrag);
172 spin_unlock(&root->fs_info->defrag_inodes_lock);
173 return 0;
174}
175
176/*
177 * must be called with the defrag_inodes lock held
178 */
179struct inode_defrag *btrfs_find_defrag_inode(struct btrfs_fs_info *info,
180 u64 root, u64 ino,
181 struct rb_node **next)
182{
183 struct inode_defrag *entry = NULL;
184 struct inode_defrag tmp;
185 struct rb_node *p;
186 struct rb_node *parent = NULL;
187 int ret;
188
189 tmp.ino = ino;
190 tmp.root = root;
191
192 p = info->defrag_inodes.rb_node;
193 while (p) {
194 parent = p;
195 entry = rb_entry(parent, struct inode_defrag, rb_node);
196
197 ret = __compare_inode_defrag(&tmp, entry);
198 if (ret < 0)
199 p = parent->rb_left;
200 else if (ret > 0)
201 p = parent->rb_right;
202 else
203 return entry;
204 }
205
206 if (next) {
207 while (parent && __compare_inode_defrag(&tmp, entry) > 0) {
208 parent = rb_next(parent);
209 entry = rb_entry(parent, struct inode_defrag, rb_node);
210 }
211 *next = parent;
212 }
213 return NULL;
214}
215
216/*
217 * run through the list of inodes in the FS that need
218 * defragging
219 */
220int btrfs_run_defrag_inodes(struct btrfs_fs_info *fs_info)
221{
222 struct inode_defrag *defrag;
223 struct btrfs_root *inode_root;
224 struct inode *inode;
225 struct rb_node *n;
226 struct btrfs_key key;
227 struct btrfs_ioctl_defrag_range_args range;
228 u64 first_ino = 0;
229 u64 root_objectid = 0;
230 int num_defrag;
231 int defrag_batch = 1024;
232
233 memset(&range, 0, sizeof(range));
234 range.len = (u64)-1;
235
236 atomic_inc(&fs_info->defrag_running);
237 spin_lock(&fs_info->defrag_inodes_lock);
238 while(1) {
239 n = NULL;
240
241 /* find an inode to defrag */
242 defrag = btrfs_find_defrag_inode(fs_info, root_objectid,
243 first_ino, &n);
244 if (!defrag) {
245 if (n) {
246 defrag = rb_entry(n, struct inode_defrag,
247 rb_node);
248 } else if (root_objectid || first_ino) {
249 root_objectid = 0;
250 first_ino = 0;
251 continue;
252 } else {
253 break;
254 }
255 }
256
257 /* remove it from the rbtree */
258 first_ino = defrag->ino + 1;
259 root_objectid = defrag->root;
260 rb_erase(&defrag->rb_node, &fs_info->defrag_inodes);
261
262 if (btrfs_fs_closing(fs_info))
263 goto next_free;
264
265 spin_unlock(&fs_info->defrag_inodes_lock);
266
267 /* get the inode */
268 key.objectid = defrag->root;
269 btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
270 key.offset = (u64)-1;
271 inode_root = btrfs_read_fs_root_no_name(fs_info, &key);
272 if (IS_ERR(inode_root))
273 goto next;
274
275 key.objectid = defrag->ino;
276 btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
277 key.offset = 0;
278
279 inode = btrfs_iget(fs_info->sb, &key, inode_root, NULL);
280 if (IS_ERR(inode))
281 goto next;
282
283 /* do a chunk of defrag */
284 clear_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags);
285 range.start = defrag->last_offset;
286 num_defrag = btrfs_defrag_file(inode, NULL, &range, defrag->transid,
287 defrag_batch);
288 /*
289 * if we filled the whole defrag batch, there
290 * must be more work to do. Queue this defrag
291 * again
292 */
293 if (num_defrag == defrag_batch) {
294 defrag->last_offset = range.start;
295 __btrfs_add_inode_defrag(inode, defrag);
296 /*
297 * we don't want to kfree defrag, we added it back to
298 * the rbtree
299 */
300 defrag = NULL;
301 } else if (defrag->last_offset && !defrag->cycled) {
302 /*
303 * we didn't fill our defrag batch, but
304 * we didn't start at zero. Make sure we loop
305 * around to the start of the file.
306 */
307 defrag->last_offset = 0;
308 defrag->cycled = 1;
309 __btrfs_add_inode_defrag(inode, defrag);
310 defrag = NULL;
311 }
312
313 iput(inode);
314next:
315 spin_lock(&fs_info->defrag_inodes_lock);
316next_free:
317 kfree(defrag);
318 }
319 spin_unlock(&fs_info->defrag_inodes_lock);
320
321 atomic_dec(&fs_info->defrag_running);
322
323 /*
324 * during unmount, we use the transaction_wait queue to
325 * wait for the defragger to stop
326 */
327 wake_up(&fs_info->transaction_wait);
328 return 0;
329}
330
331/* simple helper to fault in pages and copy. This should go away
332 * and be replaced with calls into generic code.
333 */
334static noinline int btrfs_copy_from_user(loff_t pos, int num_pages,
335 size_t write_bytes,
336 struct page **prepared_pages,
337 struct iov_iter *i)
338{
339 size_t copied = 0;
340 size_t total_copied = 0;
341 int pg = 0;
342 int offset = pos & (PAGE_CACHE_SIZE - 1);
343
344 while (write_bytes > 0) {
345 size_t count = min_t(size_t,
346 PAGE_CACHE_SIZE - offset, write_bytes);
347 struct page *page = prepared_pages[pg];
348 /*
349 * Copy data from userspace to the current page
350 *
351 * Disable pagefault to avoid recursive lock since
352 * the pages are already locked
353 */
354 pagefault_disable();
355 copied = iov_iter_copy_from_user_atomic(page, i, offset, count);
356 pagefault_enable();
357
358 /* Flush processor's dcache for this page */
359 flush_dcache_page(page);
360
361 /*
362 * if we get a partial write, we can end up with
363 * partially up to date pages. These add
364 * a lot of complexity, so make sure they don't
365 * happen by forcing this copy to be retried.
366 *
367 * The rest of the btrfs_file_write code will fall
368 * back to page at a time copies after we return 0.
369 */
370 if (!PageUptodate(page) && copied < count)
371 copied = 0;
372
373 iov_iter_advance(i, copied);
374 write_bytes -= copied;
375 total_copied += copied;
376
377 /* Return to btrfs_file_aio_write to fault page */
378 if (unlikely(copied == 0))
379 break;
380
381 if (unlikely(copied < PAGE_CACHE_SIZE - offset)) {
382 offset += copied;
383 } else {
384 pg++;
385 offset = 0;
386 }
387 }
388 return total_copied;
389}
390
391/*
392 * unlocks pages after btrfs_file_write is done with them
393 */
394void btrfs_drop_pages(struct page **pages, size_t num_pages)
395{
396 size_t i;
397 for (i = 0; i < num_pages; i++) {
398 /* page checked is some magic around finding pages that
399 * have been modified without going through btrfs_set_page_dirty
400 * clear it here
401 */
402 ClearPageChecked(pages[i]);
403 unlock_page(pages[i]);
404 mark_page_accessed(pages[i]);
405 page_cache_release(pages[i]);
406 }
407}
408
409/*
410 * after copy_from_user, pages need to be dirtied and we need to make
411 * sure holes are created between the current EOF and the start of
412 * any next extents (if required).
413 *
414 * this also makes the decision about creating an inline extent vs
415 * doing real data extents, marking pages dirty and delalloc as required.
416 */
417int btrfs_dirty_pages(struct btrfs_root *root, struct inode *inode,
418 struct page **pages, size_t num_pages,
419 loff_t pos, size_t write_bytes,
420 struct extent_state **cached)
421{
422 int err = 0;
423 int i;
424 u64 num_bytes;
425 u64 start_pos;
426 u64 end_of_last_block;
427 u64 end_pos = pos + write_bytes;
428 loff_t isize = i_size_read(inode);
429
430 start_pos = pos & ~((u64)root->sectorsize - 1);
431 num_bytes = (write_bytes + pos - start_pos +
432 root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
433
434 end_of_last_block = start_pos + num_bytes - 1;
435 err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block,
436 cached);
437 if (err)
438 return err;
439
440 for (i = 0; i < num_pages; i++) {
441 struct page *p = pages[i];
442 SetPageUptodate(p);
443 ClearPageChecked(p);
444 set_page_dirty(p);
445 }
446
447 /*
448 * we've only changed i_size in ram, and we haven't updated
449 * the disk i_size. There is no need to log the inode
450 * at this time.
451 */
452 if (end_pos > isize)
453 i_size_write(inode, end_pos);
454 return 0;
455}
456
457/*
458 * this drops all the extents in the cache that intersect the range
459 * [start, end]. Existing extents are split as required.
460 */
461int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
462 int skip_pinned)
463{
464 struct extent_map *em;
465 struct extent_map *split = NULL;
466 struct extent_map *split2 = NULL;
467 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
468 u64 len = end - start + 1;
469 int ret;
470 int testend = 1;
471 unsigned long flags;
472 int compressed = 0;
473
474 WARN_ON(end < start);
475 if (end == (u64)-1) {
476 len = (u64)-1;
477 testend = 0;
478 }
479 while (1) {
480 if (!split)
481 split = alloc_extent_map();
482 if (!split2)
483 split2 = alloc_extent_map();
484 BUG_ON(!split || !split2); /* -ENOMEM */
485
486 write_lock(&em_tree->lock);
487 em = lookup_extent_mapping(em_tree, start, len);
488 if (!em) {
489 write_unlock(&em_tree->lock);
490 break;
491 }
492 flags = em->flags;
493 if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
494 if (testend && em->start + em->len >= start + len) {
495 free_extent_map(em);
496 write_unlock(&em_tree->lock);
497 break;
498 }
499 start = em->start + em->len;
500 if (testend)
501 len = start + len - (em->start + em->len);
502 free_extent_map(em);
503 write_unlock(&em_tree->lock);
504 continue;
505 }
506 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
507 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
508 remove_extent_mapping(em_tree, em);
509
510 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
511 em->start < start) {
512 split->start = em->start;
513 split->len = start - em->start;
514 split->orig_start = em->orig_start;
515 split->block_start = em->block_start;
516
517 if (compressed)
518 split->block_len = em->block_len;
519 else
520 split->block_len = split->len;
521
522 split->bdev = em->bdev;
523 split->flags = flags;
524 split->compress_type = em->compress_type;
525 ret = add_extent_mapping(em_tree, split);
526 BUG_ON(ret); /* Logic error */
527 free_extent_map(split);
528 split = split2;
529 split2 = NULL;
530 }
531 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
532 testend && em->start + em->len > start + len) {
533 u64 diff = start + len - em->start;
534
535 split->start = start + len;
536 split->len = em->start + em->len - (start + len);
537 split->bdev = em->bdev;
538 split->flags = flags;
539 split->compress_type = em->compress_type;
540
541 if (compressed) {
542 split->block_len = em->block_len;
543 split->block_start = em->block_start;
544 split->orig_start = em->orig_start;
545 } else {
546 split->block_len = split->len;
547 split->block_start = em->block_start + diff;
548 split->orig_start = split->start;
549 }
550
551 ret = add_extent_mapping(em_tree, split);
552 BUG_ON(ret); /* Logic error */
553 free_extent_map(split);
554 split = NULL;
555 }
556 write_unlock(&em_tree->lock);
557
558 /* once for us */
559 free_extent_map(em);
560 /* once for the tree*/
561 free_extent_map(em);
562 }
563 if (split)
564 free_extent_map(split);
565 if (split2)
566 free_extent_map(split2);
567 return 0;
568}
569
570/*
571 * this is very complex, but the basic idea is to drop all extents
572 * in the range start - end. hint_block is filled in with a block number
573 * that would be a good hint to the block allocator for this file.
574 *
575 * If an extent intersects the range but is not entirely inside the range
576 * it is either truncated or split. Anything entirely inside the range
577 * is deleted from the tree.
578 */
579int btrfs_drop_extents(struct btrfs_trans_handle *trans, struct inode *inode,
580 u64 start, u64 end, u64 *hint_byte, int drop_cache)
581{
582 struct btrfs_root *root = BTRFS_I(inode)->root;
583 struct extent_buffer *leaf;
584 struct btrfs_file_extent_item *fi;
585 struct btrfs_path *path;
586 struct btrfs_key key;
587 struct btrfs_key new_key;
588 u64 ino = btrfs_ino(inode);
589 u64 search_start = start;
590 u64 disk_bytenr = 0;
591 u64 num_bytes = 0;
592 u64 extent_offset = 0;
593 u64 extent_end = 0;
594 int del_nr = 0;
595 int del_slot = 0;
596 int extent_type;
597 int recow;
598 int ret;
599 int modify_tree = -1;
600
601 if (drop_cache)
602 btrfs_drop_extent_cache(inode, start, end - 1, 0);
603
604 path = btrfs_alloc_path();
605 if (!path)
606 return -ENOMEM;
607
608 if (start >= BTRFS_I(inode)->disk_i_size)
609 modify_tree = 0;
610
611 while (1) {
612 recow = 0;
613 ret = btrfs_lookup_file_extent(trans, root, path, ino,
614 search_start, modify_tree);
615 if (ret < 0)
616 break;
617 if (ret > 0 && path->slots[0] > 0 && search_start == start) {
618 leaf = path->nodes[0];
619 btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
620 if (key.objectid == ino &&
621 key.type == BTRFS_EXTENT_DATA_KEY)
622 path->slots[0]--;
623 }
624 ret = 0;
625next_slot:
626 leaf = path->nodes[0];
627 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
628 BUG_ON(del_nr > 0);
629 ret = btrfs_next_leaf(root, path);
630 if (ret < 0)
631 break;
632 if (ret > 0) {
633 ret = 0;
634 break;
635 }
636 leaf = path->nodes[0];
637 recow = 1;
638 }
639
640 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
641 if (key.objectid > ino ||
642 key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= end)
643 break;
644
645 fi = btrfs_item_ptr(leaf, path->slots[0],
646 struct btrfs_file_extent_item);
647 extent_type = btrfs_file_extent_type(leaf, fi);
648
649 if (extent_type == BTRFS_FILE_EXTENT_REG ||
650 extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
651 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
652 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
653 extent_offset = btrfs_file_extent_offset(leaf, fi);
654 extent_end = key.offset +
655 btrfs_file_extent_num_bytes(leaf, fi);
656 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
657 extent_end = key.offset +
658 btrfs_file_extent_inline_len(leaf, fi);
659 } else {
660 WARN_ON(1);
661 extent_end = search_start;
662 }
663
664 if (extent_end <= search_start) {
665 path->slots[0]++;
666 goto next_slot;
667 }
668
669 search_start = max(key.offset, start);
670 if (recow || !modify_tree) {
671 modify_tree = -1;
672 btrfs_release_path(path);
673 continue;
674 }
675
676 /*
677 * | - range to drop - |
678 * | -------- extent -------- |
679 */
680 if (start > key.offset && end < extent_end) {
681 BUG_ON(del_nr > 0);
682 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
683
684 memcpy(&new_key, &key, sizeof(new_key));
685 new_key.offset = start;
686 ret = btrfs_duplicate_item(trans, root, path,
687 &new_key);
688 if (ret == -EAGAIN) {
689 btrfs_release_path(path);
690 continue;
691 }
692 if (ret < 0)
693 break;
694
695 leaf = path->nodes[0];
696 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
697 struct btrfs_file_extent_item);
698 btrfs_set_file_extent_num_bytes(leaf, fi,
699 start - key.offset);
700
701 fi = btrfs_item_ptr(leaf, path->slots[0],
702 struct btrfs_file_extent_item);
703
704 extent_offset += start - key.offset;
705 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
706 btrfs_set_file_extent_num_bytes(leaf, fi,
707 extent_end - start);
708 btrfs_mark_buffer_dirty(leaf);
709
710 if (disk_bytenr > 0) {
711 ret = btrfs_inc_extent_ref(trans, root,
712 disk_bytenr, num_bytes, 0,
713 root->root_key.objectid,
714 new_key.objectid,
715 start - extent_offset, 0);
716 BUG_ON(ret); /* -ENOMEM */
717 *hint_byte = disk_bytenr;
718 }
719 key.offset = start;
720 }
721 /*
722 * | ---- range to drop ----- |
723 * | -------- extent -------- |
724 */
725 if (start <= key.offset && end < extent_end) {
726 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
727
728 memcpy(&new_key, &key, sizeof(new_key));
729 new_key.offset = end;
730 btrfs_set_item_key_safe(trans, root, path, &new_key);
731
732 extent_offset += end - key.offset;
733 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
734 btrfs_set_file_extent_num_bytes(leaf, fi,
735 extent_end - end);
736 btrfs_mark_buffer_dirty(leaf);
737 if (disk_bytenr > 0) {
738 inode_sub_bytes(inode, end - key.offset);
739 *hint_byte = disk_bytenr;
740 }
741 break;
742 }
743
744 search_start = extent_end;
745 /*
746 * | ---- range to drop ----- |
747 * | -------- extent -------- |
748 */
749 if (start > key.offset && end >= extent_end) {
750 BUG_ON(del_nr > 0);
751 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
752
753 btrfs_set_file_extent_num_bytes(leaf, fi,
754 start - key.offset);
755 btrfs_mark_buffer_dirty(leaf);
756 if (disk_bytenr > 0) {
757 inode_sub_bytes(inode, extent_end - start);
758 *hint_byte = disk_bytenr;
759 }
760 if (end == extent_end)
761 break;
762
763 path->slots[0]++;
764 goto next_slot;
765 }
766
767 /*
768 * | ---- range to drop ----- |
769 * | ------ extent ------ |
770 */
771 if (start <= key.offset && end >= extent_end) {
772 if (del_nr == 0) {
773 del_slot = path->slots[0];
774 del_nr = 1;
775 } else {
776 BUG_ON(del_slot + del_nr != path->slots[0]);
777 del_nr++;
778 }
779
780 if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
781 inode_sub_bytes(inode,
782 extent_end - key.offset);
783 extent_end = ALIGN(extent_end,
784 root->sectorsize);
785 } else if (disk_bytenr > 0) {
786 ret = btrfs_free_extent(trans, root,
787 disk_bytenr, num_bytes, 0,
788 root->root_key.objectid,
789 key.objectid, key.offset -
790 extent_offset, 0);
791 BUG_ON(ret); /* -ENOMEM */
792 inode_sub_bytes(inode,
793 extent_end - key.offset);
794 *hint_byte = disk_bytenr;
795 }
796
797 if (end == extent_end)
798 break;
799
800 if (path->slots[0] + 1 < btrfs_header_nritems(leaf)) {
801 path->slots[0]++;
802 goto next_slot;
803 }
804
805 ret = btrfs_del_items(trans, root, path, del_slot,
806 del_nr);
807 if (ret) {
808 btrfs_abort_transaction(trans, root, ret);
809 goto out;
810 }
811
812 del_nr = 0;
813 del_slot = 0;
814
815 btrfs_release_path(path);
816 continue;
817 }
818
819 BUG_ON(1);
820 }
821
822 if (!ret && del_nr > 0) {
823 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
824 if (ret)
825 btrfs_abort_transaction(trans, root, ret);
826 }
827
828out:
829 btrfs_free_path(path);
830 return ret;
831}
832
833static int extent_mergeable(struct extent_buffer *leaf, int slot,
834 u64 objectid, u64 bytenr, u64 orig_offset,
835 u64 *start, u64 *end)
836{
837 struct btrfs_file_extent_item *fi;
838 struct btrfs_key key;
839 u64 extent_end;
840
841 if (slot < 0 || slot >= btrfs_header_nritems(leaf))
842 return 0;
843
844 btrfs_item_key_to_cpu(leaf, &key, slot);
845 if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
846 return 0;
847
848 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
849 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
850 btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
851 btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset ||
852 btrfs_file_extent_compression(leaf, fi) ||
853 btrfs_file_extent_encryption(leaf, fi) ||
854 btrfs_file_extent_other_encoding(leaf, fi))
855 return 0;
856
857 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
858 if ((*start && *start != key.offset) || (*end && *end != extent_end))
859 return 0;
860
861 *start = key.offset;
862 *end = extent_end;
863 return 1;
864}
865
866/*
867 * Mark extent in the range start - end as written.
868 *
869 * This changes extent type from 'pre-allocated' to 'regular'. If only
870 * part of extent is marked as written, the extent will be split into
871 * two or three.
872 */
873int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
874 struct inode *inode, u64 start, u64 end)
875{
876 struct btrfs_root *root = BTRFS_I(inode)->root;
877 struct extent_buffer *leaf;
878 struct btrfs_path *path;
879 struct btrfs_file_extent_item *fi;
880 struct btrfs_key key;
881 struct btrfs_key new_key;
882 u64 bytenr;
883 u64 num_bytes;
884 u64 extent_end;
885 u64 orig_offset;
886 u64 other_start;
887 u64 other_end;
888 u64 split;
889 int del_nr = 0;
890 int del_slot = 0;
891 int recow;
892 int ret;
893 u64 ino = btrfs_ino(inode);
894
895 btrfs_drop_extent_cache(inode, start, end - 1, 0);
896
897 path = btrfs_alloc_path();
898 if (!path)
899 return -ENOMEM;
900again:
901 recow = 0;
902 split = start;
903 key.objectid = ino;
904 key.type = BTRFS_EXTENT_DATA_KEY;
905 key.offset = split;
906
907 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
908 if (ret < 0)
909 goto out;
910 if (ret > 0 && path->slots[0] > 0)
911 path->slots[0]--;
912
913 leaf = path->nodes[0];
914 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
915 BUG_ON(key.objectid != ino || key.type != BTRFS_EXTENT_DATA_KEY);
916 fi = btrfs_item_ptr(leaf, path->slots[0],
917 struct btrfs_file_extent_item);
918 BUG_ON(btrfs_file_extent_type(leaf, fi) !=
919 BTRFS_FILE_EXTENT_PREALLOC);
920 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
921 BUG_ON(key.offset > start || extent_end < end);
922
923 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
924 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
925 orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
926 memcpy(&new_key, &key, sizeof(new_key));
927
928 if (start == key.offset && end < extent_end) {
929 other_start = 0;
930 other_end = start;
931 if (extent_mergeable(leaf, path->slots[0] - 1,
932 ino, bytenr, orig_offset,
933 &other_start, &other_end)) {
934 new_key.offset = end;
935 btrfs_set_item_key_safe(trans, root, path, &new_key);
936 fi = btrfs_item_ptr(leaf, path->slots[0],
937 struct btrfs_file_extent_item);
938 btrfs_set_file_extent_num_bytes(leaf, fi,
939 extent_end - end);
940 btrfs_set_file_extent_offset(leaf, fi,
941 end - orig_offset);
942 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
943 struct btrfs_file_extent_item);
944 btrfs_set_file_extent_num_bytes(leaf, fi,
945 end - other_start);
946 btrfs_mark_buffer_dirty(leaf);
947 goto out;
948 }
949 }
950
951 if (start > key.offset && end == extent_end) {
952 other_start = end;
953 other_end = 0;
954 if (extent_mergeable(leaf, path->slots[0] + 1,
955 ino, bytenr, orig_offset,
956 &other_start, &other_end)) {
957 fi = btrfs_item_ptr(leaf, path->slots[0],
958 struct btrfs_file_extent_item);
959 btrfs_set_file_extent_num_bytes(leaf, fi,
960 start - key.offset);
961 path->slots[0]++;
962 new_key.offset = start;
963 btrfs_set_item_key_safe(trans, root, path, &new_key);
964
965 fi = btrfs_item_ptr(leaf, path->slots[0],
966 struct btrfs_file_extent_item);
967 btrfs_set_file_extent_num_bytes(leaf, fi,
968 other_end - start);
969 btrfs_set_file_extent_offset(leaf, fi,
970 start - orig_offset);
971 btrfs_mark_buffer_dirty(leaf);
972 goto out;
973 }
974 }
975
976 while (start > key.offset || end < extent_end) {
977 if (key.offset == start)
978 split = end;
979
980 new_key.offset = split;
981 ret = btrfs_duplicate_item(trans, root, path, &new_key);
982 if (ret == -EAGAIN) {
983 btrfs_release_path(path);
984 goto again;
985 }
986 if (ret < 0) {
987 btrfs_abort_transaction(trans, root, ret);
988 goto out;
989 }
990
991 leaf = path->nodes[0];
992 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
993 struct btrfs_file_extent_item);
994 btrfs_set_file_extent_num_bytes(leaf, fi,
995 split - key.offset);
996
997 fi = btrfs_item_ptr(leaf, path->slots[0],
998 struct btrfs_file_extent_item);
999
1000 btrfs_set_file_extent_offset(leaf, fi, split - orig_offset);
1001 btrfs_set_file_extent_num_bytes(leaf, fi,
1002 extent_end - split);
1003 btrfs_mark_buffer_dirty(leaf);
1004
1005 ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0,
1006 root->root_key.objectid,
1007 ino, orig_offset, 0);
1008 BUG_ON(ret); /* -ENOMEM */
1009
1010 if (split == start) {
1011 key.offset = start;
1012 } else {
1013 BUG_ON(start != key.offset);
1014 path->slots[0]--;
1015 extent_end = end;
1016 }
1017 recow = 1;
1018 }
1019
1020 other_start = end;
1021 other_end = 0;
1022 if (extent_mergeable(leaf, path->slots[0] + 1,
1023 ino, bytenr, orig_offset,
1024 &other_start, &other_end)) {
1025 if (recow) {
1026 btrfs_release_path(path);
1027 goto again;
1028 }
1029 extent_end = other_end;
1030 del_slot = path->slots[0] + 1;
1031 del_nr++;
1032 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1033 0, root->root_key.objectid,
1034 ino, orig_offset, 0);
1035 BUG_ON(ret); /* -ENOMEM */
1036 }
1037 other_start = 0;
1038 other_end = start;
1039 if (extent_mergeable(leaf, path->slots[0] - 1,
1040 ino, bytenr, orig_offset,
1041 &other_start, &other_end)) {
1042 if (recow) {
1043 btrfs_release_path(path);
1044 goto again;
1045 }
1046 key.offset = other_start;
1047 del_slot = path->slots[0];
1048 del_nr++;
1049 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1050 0, root->root_key.objectid,
1051 ino, orig_offset, 0);
1052 BUG_ON(ret); /* -ENOMEM */
1053 }
1054 if (del_nr == 0) {
1055 fi = btrfs_item_ptr(leaf, path->slots[0],
1056 struct btrfs_file_extent_item);
1057 btrfs_set_file_extent_type(leaf, fi,
1058 BTRFS_FILE_EXTENT_REG);
1059 btrfs_mark_buffer_dirty(leaf);
1060 } else {
1061 fi = btrfs_item_ptr(leaf, del_slot - 1,
1062 struct btrfs_file_extent_item);
1063 btrfs_set_file_extent_type(leaf, fi,
1064 BTRFS_FILE_EXTENT_REG);
1065 btrfs_set_file_extent_num_bytes(leaf, fi,
1066 extent_end - key.offset);
1067 btrfs_mark_buffer_dirty(leaf);
1068
1069 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
1070 if (ret < 0) {
1071 btrfs_abort_transaction(trans, root, ret);
1072 goto out;
1073 }
1074 }
1075out:
1076 btrfs_free_path(path);
1077 return 0;
1078}
1079
1080/*
1081 * on error we return an unlocked page and the error value
1082 * on success we return a locked page and 0
1083 */
1084static int prepare_uptodate_page(struct page *page, u64 pos,
1085 bool force_uptodate)
1086{
1087 int ret = 0;
1088
1089 if (((pos & (PAGE_CACHE_SIZE - 1)) || force_uptodate) &&
1090 !PageUptodate(page)) {
1091 ret = btrfs_readpage(NULL, page);
1092 if (ret)
1093 return ret;
1094 lock_page(page);
1095 if (!PageUptodate(page)) {
1096 unlock_page(page);
1097 return -EIO;
1098 }
1099 }
1100 return 0;
1101}
1102
1103/*
1104 * this gets pages into the page cache and locks them down, it also properly
1105 * waits for data=ordered extents to finish before allowing the pages to be
1106 * modified.
1107 */
1108static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
1109 struct page **pages, size_t num_pages,
1110 loff_t pos, unsigned long first_index,
1111 size_t write_bytes, bool force_uptodate)
1112{
1113 struct extent_state *cached_state = NULL;
1114 int i;
1115 unsigned long index = pos >> PAGE_CACHE_SHIFT;
1116 struct inode *inode = fdentry(file)->d_inode;
1117 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
1118 int err = 0;
1119 int faili = 0;
1120 u64 start_pos;
1121 u64 last_pos;
1122
1123 start_pos = pos & ~((u64)root->sectorsize - 1);
1124 last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
1125
1126again:
1127 for (i = 0; i < num_pages; i++) {
1128 pages[i] = find_or_create_page(inode->i_mapping, index + i,
1129 mask | __GFP_WRITE);
1130 if (!pages[i]) {
1131 faili = i - 1;
1132 err = -ENOMEM;
1133 goto fail;
1134 }
1135
1136 if (i == 0)
1137 err = prepare_uptodate_page(pages[i], pos,
1138 force_uptodate);
1139 if (i == num_pages - 1)
1140 err = prepare_uptodate_page(pages[i],
1141 pos + write_bytes, false);
1142 if (err) {
1143 page_cache_release(pages[i]);
1144 faili = i - 1;
1145 goto fail;
1146 }
1147 wait_on_page_writeback(pages[i]);
1148 }
1149 err = 0;
1150 if (start_pos < inode->i_size) {
1151 struct btrfs_ordered_extent *ordered;
1152 lock_extent_bits(&BTRFS_I(inode)->io_tree,
1153 start_pos, last_pos - 1, 0, &cached_state);
1154 ordered = btrfs_lookup_first_ordered_extent(inode,
1155 last_pos - 1);
1156 if (ordered &&
1157 ordered->file_offset + ordered->len > start_pos &&
1158 ordered->file_offset < last_pos) {
1159 btrfs_put_ordered_extent(ordered);
1160 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1161 start_pos, last_pos - 1,
1162 &cached_state, GFP_NOFS);
1163 for (i = 0; i < num_pages; i++) {
1164 unlock_page(pages[i]);
1165 page_cache_release(pages[i]);
1166 }
1167 btrfs_wait_ordered_range(inode, start_pos,
1168 last_pos - start_pos);
1169 goto again;
1170 }
1171 if (ordered)
1172 btrfs_put_ordered_extent(ordered);
1173
1174 clear_extent_bit(&BTRFS_I(inode)->io_tree, start_pos,
1175 last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC |
1176 EXTENT_DO_ACCOUNTING, 0, 0, &cached_state,
1177 GFP_NOFS);
1178 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1179 start_pos, last_pos - 1, &cached_state,
1180 GFP_NOFS);
1181 }
1182 for (i = 0; i < num_pages; i++) {
1183 if (clear_page_dirty_for_io(pages[i]))
1184 account_page_redirty(pages[i]);
1185 set_page_extent_mapped(pages[i]);
1186 WARN_ON(!PageLocked(pages[i]));
1187 }
1188 return 0;
1189fail:
1190 while (faili >= 0) {
1191 unlock_page(pages[faili]);
1192 page_cache_release(pages[faili]);
1193 faili--;
1194 }
1195 return err;
1196
1197}
1198
1199static noinline ssize_t __btrfs_buffered_write(struct file *file,
1200 struct iov_iter *i,
1201 loff_t pos)
1202{
1203 struct inode *inode = fdentry(file)->d_inode;
1204 struct btrfs_root *root = BTRFS_I(inode)->root;
1205 struct page **pages = NULL;
1206 unsigned long first_index;
1207 size_t num_written = 0;
1208 int nrptrs;
1209 int ret = 0;
1210 bool force_page_uptodate = false;
1211
1212 nrptrs = min((iov_iter_count(i) + PAGE_CACHE_SIZE - 1) /
1213 PAGE_CACHE_SIZE, PAGE_CACHE_SIZE /
1214 (sizeof(struct page *)));
1215 nrptrs = min(nrptrs, current->nr_dirtied_pause - current->nr_dirtied);
1216 nrptrs = max(nrptrs, 8);
1217 pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
1218 if (!pages)
1219 return -ENOMEM;
1220
1221 first_index = pos >> PAGE_CACHE_SHIFT;
1222
1223 while (iov_iter_count(i) > 0) {
1224 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
1225 size_t write_bytes = min(iov_iter_count(i),
1226 nrptrs * (size_t)PAGE_CACHE_SIZE -
1227 offset);
1228 size_t num_pages = (write_bytes + offset +
1229 PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
1230 size_t dirty_pages;
1231 size_t copied;
1232
1233 WARN_ON(num_pages > nrptrs);
1234
1235 /*
1236 * Fault pages before locking them in prepare_pages
1237 * to avoid recursive lock
1238 */
1239 if (unlikely(iov_iter_fault_in_readable(i, write_bytes))) {
1240 ret = -EFAULT;
1241 break;
1242 }
1243
1244 ret = btrfs_delalloc_reserve_space(inode,
1245 num_pages << PAGE_CACHE_SHIFT);
1246 if (ret)
1247 break;
1248
1249 /*
1250 * This is going to setup the pages array with the number of
1251 * pages we want, so we don't really need to worry about the
1252 * contents of pages from loop to loop
1253 */
1254 ret = prepare_pages(root, file, pages, num_pages,
1255 pos, first_index, write_bytes,
1256 force_page_uptodate);
1257 if (ret) {
1258 btrfs_delalloc_release_space(inode,
1259 num_pages << PAGE_CACHE_SHIFT);
1260 break;
1261 }
1262
1263 copied = btrfs_copy_from_user(pos, num_pages,
1264 write_bytes, pages, i);
1265
1266 /*
1267 * if we have trouble faulting in the pages, fall
1268 * back to one page at a time
1269 */
1270 if (copied < write_bytes)
1271 nrptrs = 1;
1272
1273 if (copied == 0) {
1274 force_page_uptodate = true;
1275 dirty_pages = 0;
1276 } else {
1277 force_page_uptodate = false;
1278 dirty_pages = (copied + offset +
1279 PAGE_CACHE_SIZE - 1) >>
1280 PAGE_CACHE_SHIFT;
1281 }
1282
1283 /*
1284 * If we had a short copy we need to release the excess delaloc
1285 * bytes we reserved. We need to increment outstanding_extents
1286 * because btrfs_delalloc_release_space will decrement it, but
1287 * we still have an outstanding extent for the chunk we actually
1288 * managed to copy.
1289 */
1290 if (num_pages > dirty_pages) {
1291 if (copied > 0) {
1292 spin_lock(&BTRFS_I(inode)->lock);
1293 BTRFS_I(inode)->outstanding_extents++;
1294 spin_unlock(&BTRFS_I(inode)->lock);
1295 }
1296 btrfs_delalloc_release_space(inode,
1297 (num_pages - dirty_pages) <<
1298 PAGE_CACHE_SHIFT);
1299 }
1300
1301 if (copied > 0) {
1302 ret = btrfs_dirty_pages(root, inode, pages,
1303 dirty_pages, pos, copied,
1304 NULL);
1305 if (ret) {
1306 btrfs_delalloc_release_space(inode,
1307 dirty_pages << PAGE_CACHE_SHIFT);
1308 btrfs_drop_pages(pages, num_pages);
1309 break;
1310 }
1311 }
1312
1313 btrfs_drop_pages(pages, num_pages);
1314
1315 cond_resched();
1316
1317 balance_dirty_pages_ratelimited_nr(inode->i_mapping,
1318 dirty_pages);
1319 if (dirty_pages < (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
1320 btrfs_btree_balance_dirty(root, 1);
1321
1322 pos += copied;
1323 num_written += copied;
1324 }
1325
1326 kfree(pages);
1327
1328 return num_written ? num_written : ret;
1329}
1330
1331static ssize_t __btrfs_direct_write(struct kiocb *iocb,
1332 const struct iovec *iov,
1333 unsigned long nr_segs, loff_t pos,
1334 loff_t *ppos, size_t count, size_t ocount)
1335{
1336 struct file *file = iocb->ki_filp;
1337 struct iov_iter i;
1338 ssize_t written;
1339 ssize_t written_buffered;
1340 loff_t endbyte;
1341 int err;
1342
1343 written = generic_file_direct_write(iocb, iov, &nr_segs, pos, ppos,
1344 count, ocount);
1345
1346 if (written < 0 || written == count)
1347 return written;
1348
1349 pos += written;
1350 count -= written;
1351 iov_iter_init(&i, iov, nr_segs, count, written);
1352 written_buffered = __btrfs_buffered_write(file, &i, pos);
1353 if (written_buffered < 0) {
1354 err = written_buffered;
1355 goto out;
1356 }
1357 endbyte = pos + written_buffered - 1;
1358 err = filemap_write_and_wait_range(file->f_mapping, pos, endbyte);
1359 if (err)
1360 goto out;
1361 written += written_buffered;
1362 *ppos = pos + written_buffered;
1363 invalidate_mapping_pages(file->f_mapping, pos >> PAGE_CACHE_SHIFT,
1364 endbyte >> PAGE_CACHE_SHIFT);
1365out:
1366 return written ? written : err;
1367}
1368
1369static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
1370 const struct iovec *iov,
1371 unsigned long nr_segs, loff_t pos)
1372{
1373 struct file *file = iocb->ki_filp;
1374 struct inode *inode = fdentry(file)->d_inode;
1375 struct btrfs_root *root = BTRFS_I(inode)->root;
1376 loff_t *ppos = &iocb->ki_pos;
1377 u64 start_pos;
1378 ssize_t num_written = 0;
1379 ssize_t err = 0;
1380 size_t count, ocount;
1381
1382 vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
1383
1384 mutex_lock(&inode->i_mutex);
1385
1386 err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
1387 if (err) {
1388 mutex_unlock(&inode->i_mutex);
1389 goto out;
1390 }
1391 count = ocount;
1392
1393 current->backing_dev_info = inode->i_mapping->backing_dev_info;
1394 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
1395 if (err) {
1396 mutex_unlock(&inode->i_mutex);
1397 goto out;
1398 }
1399
1400 if (count == 0) {
1401 mutex_unlock(&inode->i_mutex);
1402 goto out;
1403 }
1404
1405 err = file_remove_suid(file);
1406 if (err) {
1407 mutex_unlock(&inode->i_mutex);
1408 goto out;
1409 }
1410
1411 /*
1412 * If BTRFS flips readonly due to some impossible error
1413 * (fs_info->fs_state now has BTRFS_SUPER_FLAG_ERROR),
1414 * although we have opened a file as writable, we have
1415 * to stop this write operation to ensure FS consistency.
1416 */
1417 if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
1418 mutex_unlock(&inode->i_mutex);
1419 err = -EROFS;
1420 goto out;
1421 }
1422
1423 err = file_update_time(file);
1424 if (err) {
1425 mutex_unlock(&inode->i_mutex);
1426 goto out;
1427 }
1428
1429 start_pos = round_down(pos, root->sectorsize);
1430 if (start_pos > i_size_read(inode)) {
1431 err = btrfs_cont_expand(inode, i_size_read(inode), start_pos);
1432 if (err) {
1433 mutex_unlock(&inode->i_mutex);
1434 goto out;
1435 }
1436 }
1437
1438 if (unlikely(file->f_flags & O_DIRECT)) {
1439 num_written = __btrfs_direct_write(iocb, iov, nr_segs,
1440 pos, ppos, count, ocount);
1441 } else {
1442 struct iov_iter i;
1443
1444 iov_iter_init(&i, iov, nr_segs, count, num_written);
1445
1446 num_written = __btrfs_buffered_write(file, &i, pos);
1447 if (num_written > 0)
1448 *ppos = pos + num_written;
1449 }
1450
1451 mutex_unlock(&inode->i_mutex);
1452
1453 /*
1454 * we want to make sure fsync finds this change
1455 * but we haven't joined a transaction running right now.
1456 *
1457 * Later on, someone is sure to update the inode and get the
1458 * real transid recorded.
1459 *
1460 * We set last_trans now to the fs_info generation + 1,
1461 * this will either be one more than the running transaction
1462 * or the generation used for the next transaction if there isn't
1463 * one running right now.
1464 */
1465 BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
1466 if (num_written > 0 || num_written == -EIOCBQUEUED) {
1467 err = generic_write_sync(file, pos, num_written);
1468 if (err < 0 && num_written > 0)
1469 num_written = err;
1470 }
1471out:
1472 current->backing_dev_info = NULL;
1473 return num_written ? num_written : err;
1474}
1475
1476int btrfs_release_file(struct inode *inode, struct file *filp)
1477{
1478 /*
1479 * ordered_data_close is set by settattr when we are about to truncate
1480 * a file from a non-zero size to a zero size. This tries to
1481 * flush down new bytes that may have been written if the
1482 * application were using truncate to replace a file in place.
1483 */
1484 if (test_and_clear_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
1485 &BTRFS_I(inode)->runtime_flags)) {
1486 btrfs_add_ordered_operation(NULL, BTRFS_I(inode)->root, inode);
1487 if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
1488 filemap_flush(inode->i_mapping);
1489 }
1490 if (filp->private_data)
1491 btrfs_ioctl_trans_end(filp);
1492 return 0;
1493}
1494
1495/*
1496 * fsync call for both files and directories. This logs the inode into
1497 * the tree log instead of forcing full commits whenever possible.
1498 *
1499 * It needs to call filemap_fdatawait so that all ordered extent updates are
1500 * in the metadata btree are up to date for copying to the log.
1501 *
1502 * It drops the inode mutex before doing the tree log commit. This is an
1503 * important optimization for directories because holding the mutex prevents
1504 * new operations on the dir while we write to disk.
1505 */
1506int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
1507{
1508 struct dentry *dentry = file->f_path.dentry;
1509 struct inode *inode = dentry->d_inode;
1510 struct btrfs_root *root = BTRFS_I(inode)->root;
1511 int ret = 0;
1512 struct btrfs_trans_handle *trans;
1513
1514 trace_btrfs_sync_file(file, datasync);
1515
1516 mutex_lock(&inode->i_mutex);
1517
1518 /*
1519 * we wait first, since the writeback may change the inode, also wait
1520 * ordered range does a filemape_write_and_wait_range which is why we
1521 * don't do it above like other file systems.
1522 */
1523 root->log_batch++;
1524 btrfs_wait_ordered_range(inode, start, end);
1525 root->log_batch++;
1526
1527 /*
1528 * check the transaction that last modified this inode
1529 * and see if its already been committed
1530 */
1531 if (!BTRFS_I(inode)->last_trans) {
1532 mutex_unlock(&inode->i_mutex);
1533 goto out;
1534 }
1535
1536 /*
1537 * if the last transaction that changed this file was before
1538 * the current transaction, we can bail out now without any
1539 * syncing
1540 */
1541 smp_mb();
1542 if (btrfs_inode_in_log(inode, root->fs_info->generation) ||
1543 BTRFS_I(inode)->last_trans <=
1544 root->fs_info->last_trans_committed) {
1545 BTRFS_I(inode)->last_trans = 0;
1546 mutex_unlock(&inode->i_mutex);
1547 goto out;
1548 }
1549
1550 /*
1551 * ok we haven't committed the transaction yet, lets do a commit
1552 */
1553 if (file->private_data)
1554 btrfs_ioctl_trans_end(file);
1555
1556 trans = btrfs_start_transaction(root, 0);
1557 if (IS_ERR(trans)) {
1558 ret = PTR_ERR(trans);
1559 mutex_unlock(&inode->i_mutex);
1560 goto out;
1561 }
1562
1563 ret = btrfs_log_dentry_safe(trans, root, dentry);
1564 if (ret < 0) {
1565 mutex_unlock(&inode->i_mutex);
1566 goto out;
1567 }
1568
1569 /* we've logged all the items and now have a consistent
1570 * version of the file in the log. It is possible that
1571 * someone will come in and modify the file, but that's
1572 * fine because the log is consistent on disk, and we
1573 * have references to all of the file's extents
1574 *
1575 * It is possible that someone will come in and log the
1576 * file again, but that will end up using the synchronization
1577 * inside btrfs_sync_log to keep things safe.
1578 */
1579 mutex_unlock(&inode->i_mutex);
1580
1581 if (ret != BTRFS_NO_LOG_SYNC) {
1582 if (ret > 0) {
1583 ret = btrfs_commit_transaction(trans, root);
1584 } else {
1585 ret = btrfs_sync_log(trans, root);
1586 if (ret == 0)
1587 ret = btrfs_end_transaction(trans, root);
1588 else
1589 ret = btrfs_commit_transaction(trans, root);
1590 }
1591 } else {
1592 ret = btrfs_end_transaction(trans, root);
1593 }
1594out:
1595 return ret > 0 ? -EIO : ret;
1596}
1597
1598static const struct vm_operations_struct btrfs_file_vm_ops = {
1599 .fault = filemap_fault,
1600 .page_mkwrite = btrfs_page_mkwrite,
1601};
1602
1603static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
1604{
1605 struct address_space *mapping = filp->f_mapping;
1606
1607 if (!mapping->a_ops->readpage)
1608 return -ENOEXEC;
1609
1610 file_accessed(filp);
1611 vma->vm_ops = &btrfs_file_vm_ops;
1612 vma->vm_flags |= VM_CAN_NONLINEAR;
1613
1614 return 0;
1615}
1616
1617static long btrfs_fallocate(struct file *file, int mode,
1618 loff_t offset, loff_t len)
1619{
1620 struct inode *inode = file->f_path.dentry->d_inode;
1621 struct extent_state *cached_state = NULL;
1622 u64 cur_offset;
1623 u64 last_byte;
1624 u64 alloc_start;
1625 u64 alloc_end;
1626 u64 alloc_hint = 0;
1627 u64 locked_end;
1628 u64 mask = BTRFS_I(inode)->root->sectorsize - 1;
1629 struct extent_map *em;
1630 int ret;
1631
1632 alloc_start = offset & ~mask;
1633 alloc_end = (offset + len + mask) & ~mask;
1634
1635 /* We only support the FALLOC_FL_KEEP_SIZE mode */
1636 if (mode & ~FALLOC_FL_KEEP_SIZE)
1637 return -EOPNOTSUPP;
1638
1639 /*
1640 * Make sure we have enough space before we do the
1641 * allocation.
1642 */
1643 ret = btrfs_check_data_free_space(inode, len);
1644 if (ret)
1645 return ret;
1646
1647 /*
1648 * wait for ordered IO before we have any locks. We'll loop again
1649 * below with the locks held.
1650 */
1651 btrfs_wait_ordered_range(inode, alloc_start, alloc_end - alloc_start);
1652
1653 mutex_lock(&inode->i_mutex);
1654 ret = inode_newsize_ok(inode, alloc_end);
1655 if (ret)
1656 goto out;
1657
1658 if (alloc_start > inode->i_size) {
1659 ret = btrfs_cont_expand(inode, i_size_read(inode),
1660 alloc_start);
1661 if (ret)
1662 goto out;
1663 }
1664
1665 locked_end = alloc_end - 1;
1666 while (1) {
1667 struct btrfs_ordered_extent *ordered;
1668
1669 /* the extent lock is ordered inside the running
1670 * transaction
1671 */
1672 lock_extent_bits(&BTRFS_I(inode)->io_tree, alloc_start,
1673 locked_end, 0, &cached_state);
1674 ordered = btrfs_lookup_first_ordered_extent(inode,
1675 alloc_end - 1);
1676 if (ordered &&
1677 ordered->file_offset + ordered->len > alloc_start &&
1678 ordered->file_offset < alloc_end) {
1679 btrfs_put_ordered_extent(ordered);
1680 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1681 alloc_start, locked_end,
1682 &cached_state, GFP_NOFS);
1683 /*
1684 * we can't wait on the range with the transaction
1685 * running or with the extent lock held
1686 */
1687 btrfs_wait_ordered_range(inode, alloc_start,
1688 alloc_end - alloc_start);
1689 } else {
1690 if (ordered)
1691 btrfs_put_ordered_extent(ordered);
1692 break;
1693 }
1694 }
1695
1696 cur_offset = alloc_start;
1697 while (1) {
1698 u64 actual_end;
1699
1700 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
1701 alloc_end - cur_offset, 0);
1702 if (IS_ERR_OR_NULL(em)) {
1703 if (!em)
1704 ret = -ENOMEM;
1705 else
1706 ret = PTR_ERR(em);
1707 break;
1708 }
1709 last_byte = min(extent_map_end(em), alloc_end);
1710 actual_end = min_t(u64, extent_map_end(em), offset + len);
1711 last_byte = (last_byte + mask) & ~mask;
1712
1713 if (em->block_start == EXTENT_MAP_HOLE ||
1714 (cur_offset >= inode->i_size &&
1715 !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
1716 ret = btrfs_prealloc_file_range(inode, mode, cur_offset,
1717 last_byte - cur_offset,
1718 1 << inode->i_blkbits,
1719 offset + len,
1720 &alloc_hint);
1721
1722 if (ret < 0) {
1723 free_extent_map(em);
1724 break;
1725 }
1726 } else if (actual_end > inode->i_size &&
1727 !(mode & FALLOC_FL_KEEP_SIZE)) {
1728 /*
1729 * We didn't need to allocate any more space, but we
1730 * still extended the size of the file so we need to
1731 * update i_size.
1732 */
1733 inode->i_ctime = CURRENT_TIME;
1734 i_size_write(inode, actual_end);
1735 btrfs_ordered_update_i_size(inode, actual_end, NULL);
1736 }
1737 free_extent_map(em);
1738
1739 cur_offset = last_byte;
1740 if (cur_offset >= alloc_end) {
1741 ret = 0;
1742 break;
1743 }
1744 }
1745 unlock_extent_cached(&BTRFS_I(inode)->io_tree, alloc_start, locked_end,
1746 &cached_state, GFP_NOFS);
1747out:
1748 mutex_unlock(&inode->i_mutex);
1749 /* Let go of our reservation. */
1750 btrfs_free_reserved_data_space(inode, len);
1751 return ret;
1752}
1753
1754static int find_desired_extent(struct inode *inode, loff_t *offset, int origin)
1755{
1756 struct btrfs_root *root = BTRFS_I(inode)->root;
1757 struct extent_map *em;
1758 struct extent_state *cached_state = NULL;
1759 u64 lockstart = *offset;
1760 u64 lockend = i_size_read(inode);
1761 u64 start = *offset;
1762 u64 orig_start = *offset;
1763 u64 len = i_size_read(inode);
1764 u64 last_end = 0;
1765 int ret = 0;
1766
1767 lockend = max_t(u64, root->sectorsize, lockend);
1768 if (lockend <= lockstart)
1769 lockend = lockstart + root->sectorsize;
1770
1771 len = lockend - lockstart + 1;
1772
1773 len = max_t(u64, len, root->sectorsize);
1774 if (inode->i_size == 0)
1775 return -ENXIO;
1776
1777 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend, 0,
1778 &cached_state);
1779
1780 /*
1781 * Delalloc is such a pain. If we have a hole and we have pending
1782 * delalloc for a portion of the hole we will get back a hole that
1783 * exists for the entire range since it hasn't been actually written
1784 * yet. So to take care of this case we need to look for an extent just
1785 * before the position we want in case there is outstanding delalloc
1786 * going on here.
1787 */
1788 if (origin == SEEK_HOLE && start != 0) {
1789 if (start <= root->sectorsize)
1790 em = btrfs_get_extent_fiemap(inode, NULL, 0, 0,
1791 root->sectorsize, 0);
1792 else
1793 em = btrfs_get_extent_fiemap(inode, NULL, 0,
1794 start - root->sectorsize,
1795 root->sectorsize, 0);
1796 if (IS_ERR(em)) {
1797 ret = PTR_ERR(em);
1798 goto out;
1799 }
1800 last_end = em->start + em->len;
1801 if (em->block_start == EXTENT_MAP_DELALLOC)
1802 last_end = min_t(u64, last_end, inode->i_size);
1803 free_extent_map(em);
1804 }
1805
1806 while (1) {
1807 em = btrfs_get_extent_fiemap(inode, NULL, 0, start, len, 0);
1808 if (IS_ERR(em)) {
1809 ret = PTR_ERR(em);
1810 break;
1811 }
1812
1813 if (em->block_start == EXTENT_MAP_HOLE) {
1814 if (test_bit(EXTENT_FLAG_VACANCY, &em->flags)) {
1815 if (last_end <= orig_start) {
1816 free_extent_map(em);
1817 ret = -ENXIO;
1818 break;
1819 }
1820 }
1821
1822 if (origin == SEEK_HOLE) {
1823 *offset = start;
1824 free_extent_map(em);
1825 break;
1826 }
1827 } else {
1828 if (origin == SEEK_DATA) {
1829 if (em->block_start == EXTENT_MAP_DELALLOC) {
1830 if (start >= inode->i_size) {
1831 free_extent_map(em);
1832 ret = -ENXIO;
1833 break;
1834 }
1835 }
1836
1837 *offset = start;
1838 free_extent_map(em);
1839 break;
1840 }
1841 }
1842
1843 start = em->start + em->len;
1844 last_end = em->start + em->len;
1845
1846 if (em->block_start == EXTENT_MAP_DELALLOC)
1847 last_end = min_t(u64, last_end, inode->i_size);
1848
1849 if (test_bit(EXTENT_FLAG_VACANCY, &em->flags)) {
1850 free_extent_map(em);
1851 ret = -ENXIO;
1852 break;
1853 }
1854 free_extent_map(em);
1855 cond_resched();
1856 }
1857 if (!ret)
1858 *offset = min(*offset, inode->i_size);
1859out:
1860 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
1861 &cached_state, GFP_NOFS);
1862 return ret;
1863}
1864
1865static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int origin)
1866{
1867 struct inode *inode = file->f_mapping->host;
1868 int ret;
1869
1870 mutex_lock(&inode->i_mutex);
1871 switch (origin) {
1872 case SEEK_END:
1873 case SEEK_CUR:
1874 offset = generic_file_llseek(file, offset, origin);
1875 goto out;
1876 case SEEK_DATA:
1877 case SEEK_HOLE:
1878 if (offset >= i_size_read(inode)) {
1879 mutex_unlock(&inode->i_mutex);
1880 return -ENXIO;
1881 }
1882
1883 ret = find_desired_extent(inode, &offset, origin);
1884 if (ret) {
1885 mutex_unlock(&inode->i_mutex);
1886 return ret;
1887 }
1888 }
1889
1890 if (offset < 0 && !(file->f_mode & FMODE_UNSIGNED_OFFSET)) {
1891 offset = -EINVAL;
1892 goto out;
1893 }
1894 if (offset > inode->i_sb->s_maxbytes) {
1895 offset = -EINVAL;
1896 goto out;
1897 }
1898
1899 /* Special lock needed here? */
1900 if (offset != file->f_pos) {
1901 file->f_pos = offset;
1902 file->f_version = 0;
1903 }
1904out:
1905 mutex_unlock(&inode->i_mutex);
1906 return offset;
1907}
1908
1909const struct file_operations btrfs_file_operations = {
1910 .llseek = btrfs_file_llseek,
1911 .read = do_sync_read,
1912 .write = do_sync_write,
1913 .aio_read = generic_file_aio_read,
1914 .splice_read = generic_file_splice_read,
1915 .aio_write = btrfs_file_aio_write,
1916 .mmap = btrfs_file_mmap,
1917 .open = generic_file_open,
1918 .release = btrfs_release_file,
1919 .fsync = btrfs_sync_file,
1920 .fallocate = btrfs_fallocate,
1921 .unlocked_ioctl = btrfs_ioctl,
1922#ifdef CONFIG_COMPAT
1923 .compat_ioctl = btrfs_ioctl,
1924#endif
1925};